Prior to the present invention, as shown by Crivello, U.S. Pat. No. 3,981,897, certain diarylhalonium salts were prepared by initially forming an intermediate diarylhalonium bisulfate, and thereafter the diarylhalonium bisulfate was reacted with a hexafluoro compound, such as a Group Va hexafluoride salt, for example, sodium hexafluorophosphate, potassium hexafluoroantimonate or potassium hexafluoroarsenate. The resulting diaryliodonium hexafluoro metal or metalloid salts were found to be useful as photoinitiators for a wide variety of cationically polymerizable organic materials, such as epoxy resins.
As shown by Nielands and Karele, Journal of Organic Chemistry, U.S.S.R. 6, 889 (1970) alkylaryliodonium salts were synthesized by condensing dimedone and dimedone ethylether with [hydroxy(tosyloxy)iodo]benzene.
The [hydroxy(tosylate)iodo]benzene was prepared by the reaction of the corresponding iodosobenzene diacetate with a C.sub.(1-13) organic sulfonic acid, for example, a strong alkyl or aryl sulfonic acid, such as benzenesulfonic acid, 3-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, trifluoromethanesulfonic acid, methanesulfonic acid, p-toluenesulfonic acid, etc.
We have now discovered that the aforementioned reaction of Nielands and Karele can be applied to a variety of aliphatic compounds in addition to dimedone to produce a wide variety of arylalkyliodonium tosylate salts. In addition, we have also found that a wide variety of arylalkyliodonium salts exhibiting valuable properties such as thermal initiators, and photoinitiators for various cationic polymerizable organic materials, for example, epoxy resins can be made by a straight forward metathesis between the arylalkyliodonium tosylate and polyfluoro metalloid salt in accordance with the following equation: EQU [RIY].sup.+ [QSO.sub.3 ].sup.- +XMF.sub.d .fwdarw.[RIY].sup.+ [MF.sub.d ].sup.- +QSO.sub.3 X,
where R is a C.sub.(6-13) aryl radical, Y is a monovalent aliphatic or cycloaliphatic group selected from ##STR1## R.sup.1 and R.sup.4 are selected from hydrogen and C.sub.(1-8) alkyl, R.sup.2 and R.sup.3 are ##STR2## or a mixture of ##STR3## where R.sup.7 and R.sup.8 are selected from C.sub.(1-13) organic radicals which together can form a member selected from a C.sub.(6-13) aromatic structure, C.sub.(5-13) heterocyclic structure, two C.sub.(6-13) aryl radicals, a mixture of C.sub.(1-8) alkyl radical and a C.sub.(6-13) aryl radical, and a mixture of alkyl and oxyalkyl, or alkyl and oxyaryl, and R.sup.5 and R.sup.6 are monovalent electron withdrawing groups selected from nitrile and a mixture of nitro and C.sub.(6-13) aryl, Q is a C.sub.(1-13) organic radical, X is an ion selected from hydrogen, alkali metals and alkaline earth metals, M is a metal or metalloid selected from antimony, arsenic, phosphorus and boron, and d is an integer equal to from 4-6 inclusive.